scholarly journals Effects of land water storage on global mean sea level over the past half century

2005 ◽  
Vol 32 (9) ◽  
Author(s):  
T. Ngo-Duc
Keyword(s):  
Sea Level ◽  
Water Storage ◽  
Mean Sea Level ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
Global Mean Sea Level ◽  
Past Half ◽  
Land Water ◽  
Global Mean

The rate and acceleration of the global mean sea level revisited

2020 ◽  
Author(s):  
Lorena Moreira ◽  
Anny Cazenave ◽  
Denise Cáceres ◽  
Hindumathi Palanisamy ◽  
Habib Dieng
Keyword(s):  
Thermal Expansion ◽  
Global Warming ◽  
Sea Level Rise ◽  
Interannual Variability ◽  
Sea Level ◽  
Water Storage ◽  
Mean Sea Level ◽  
Global Mean Sea Level ◽  
Land Water ◽  
Global Mean

<p>Since nearly 3 decades, high-precision satellite altimetry allows us to precisely measure the mean sea level evolution at global and regional scales. In terms of global mean, sea level is rising at a mean rate of 3.2 mm/yr. The altimetry record is also suggesting that the global mean sea level rise is accelerating. However, the exact value of the acceleration and even its mere existence are still debated. Determination of the global warming-related sea level rate and acceleration are somewhat hindered by the interannual signal caused by natural climate variability. During the recent years, several studies have shown that at interannual time scale, the global mean sea level is mostly due to ENSO-driven land water storage variations. But thermal expansion fluctuations may also contribute. Thus, to isolate the global warming signal in the global mean sea level, we need to remove the ENSO-related interannual variability. For that purpose we use the Water Gap Global Hydrological model developed by the University of Frankfurt for land water storage as well as GRACE space gravimetry data on land and empirical models based on ENSO indices. We also extract the ENSO-related signal in thermal expansion. After removing the total interannual variability signal due to both mass and steric components, we compute the evolution with time of the ‘residual’ rate of sea level rise over successive 5-year moving windows, as well as the associated acceleration. Using time series of thermal expansion and ice sheet mass balances, we also estimate the respective contributions of each component to the global mean sea level acceleration.</p>

scholarly journals Global sea-level budget 1993–present

2018 ◽  
Vol 10 (3) ◽  
pp. 1551-1590 ◽  
Author(s):  
Keyword(s):  
Sea Level ◽  
Average Rate ◽  
Deep Ocean ◽  
Grand Challenge ◽  
Mean Sea Level ◽  
Climate Research ◽  
Global Mean Sea Level ◽  
Land Water ◽  
Global Mean ◽  
Individual Mass

Abstract. Global mean sea level is an integral of changes occurring in the climate system in response to unforced climate variability as well as natural and anthropogenic forcing factors. Its temporal evolution allows changes (e.g., acceleration) to be detected in one or more components. Study of the sea-level budget provides constraints on missing or poorly known contributions, such as the unsurveyed deep ocean or the still uncertain land water component. In the context of the World Climate Research Programme Grand Challenge entitled Regional Sea Level and Coastal Impacts, an international effort involving the sea-level community worldwide has been recently initiated with the objective of assessing the various datasets used to estimate components of the sea-level budget during the altimetry era (1993 to present). These datasets are based on the combination of a broad range of space-based and in situ observations, model estimates, and algorithms. Evaluating their quality, quantifying uncertainties and identifying sources of discrepancies between component estimates is extremely useful for various applications in climate research. This effort involves several tens of scientists from about 50 research teams/institutions worldwide (www.wcrp-climate.org/grand-challenges/gc-sea-level, last access: 22 August 2018). The results presented in this paper are a synthesis of the first assessment performed during 2017–2018. We present estimates of the altimetry-based global mean sea level (average rate of 3.1 ± 0.3 mm yr−1 and acceleration of 0.1 mm yr−2 over 1993–present), as well as of the different components of the sea-level budget (http://doi.org/10.17882/54854, last access: 22 August 2018). We further examine closure of the sea-level budget, comparing the observed global mean sea level with the sum of components. Ocean thermal expansion, glaciers, Greenland and Antarctica contribute 42 %, 21 %, 15 % and 8 % to the global mean sea level over the 1993–present period. We also study the sea-level budget over 2005–present, using GRACE-based ocean mass estimates instead of the sum of individual mass components. Our results demonstrate that the global mean sea level can be closed to within 0.3 mm yr−1 (1σ). Substantial uncertainty remains for the land water storage component, as shown when examining individual mass contributions to sea level.

scholarly journals Sea-level stands from the Western Mediterranean over the past 6.5 million years

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Oana A. Dumitru ◽  
Jacqueline Austermann ◽  
Victor J. Polyak ◽  
Joan J. Fornós ◽  
Yemane Asmerom ◽  
...  
Keyword(s):  
Sea Level ◽  
Western Mediterranean ◽  
Glacial Isostatic Adjustment ◽  
Mean Sea Level ◽  
The Past ◽  
Isostatic Adjustment ◽  
Future Warming ◽  
Global Mean Sea Level ◽  
Global Mean

AbstractSea-level reconstructions are important for understanding past ice sheet variability and its response to past and future warming. Here we present Neogene and Quaternary sea-level snapshots using phreatic overgrowths on speleothems (POS) from caves on Mallorca, Spain. POS are excellent sea level index points because of their clear relationship to sea level and precise U–Pb chronology. We find that local sea-level before and at the onset of the Messinian Salinity Crisis was at 33.3 ± 0.25 m (6.54 ± 0.37 Ma) and 31.8 ± 0.25 m (5.86 ± 0.60 Ma) above present levels, respectively. We further present global mean sea level (GMSL) estimates, i.e. local sea level corrected for glacial isostatic adjustment and long-term uplift, for three other POS. The results show that GMSL during the Pliocene–Pleistocene Transition was 6.4 m (− 2.0–8.8 m) at 2.63 ± 0.11 Ma and during the beginning and the end of the Mid-Pleistocene Transition was − 1.1 m (− 5.6–2.4 m) and 5 m (1.5–8.1 m), respectively. These estimates provide important constraints for the past evolution of sea level and show that local sea level prior to the MSC was similar to the highest stand during the Pliocene, with markedly lower position afterwards.

scholarly journals Global Sea Level Budget 1993–Present

2018 ◽  
Author(s):  
Keyword(s):  
Sea Level ◽  
Average Rate ◽  
Grand Challenge ◽  
Data Sets ◽  
Mean Sea Level ◽  
Climate Research ◽  
Global Mean Sea Level ◽  
Land Water ◽  
Global Mean ◽  
Individual Mass

Abstract. Global mean sea level is an integral of changes occurring in the climate system in response to unforced climate variability as well as natural and anthropogenic forcing factors. Its temporal evolution allows detecting changes (e.g., acceleration) in one or more components. Study of the sea level budget provides constraints on missing or poorly known contributions, such as the unsurveyed deep ocean or the still uncertain land water component. In the context of the World Climate Research Programme Grand Challenge entitled ``Regional Sea Level and Coastal Impacts'', an international effort involving the sea level community worldwide has been recently initiated with the objective of assessing the various data sets used to estimate components of the sea level budget during the altimetry era (1993 to present). These data sets are based on the combination of a broad range of space-based and in situ observations, model estimates and algorithms. Evaluating their quality, quantifying uncertainties and identifying sources of discrepancies between component estimates is extremely useful for various applications in climate research. This effort involves several tens of scientists from about sixty research teams/institutions worldwide (http://www.wcrp-climate.org/grand-challenges/gc-sea-level). The results presented in this paper are a synthesis of the first assessment performed during 2017–2018. We present estimates of the altimetry-based global mean sea level (average rate of 3.1 ± 0.3 mm/yr and acceleration of 0.1 mm/yr2 over 1993–present), as well as of the different components of the sea level budget (doi:10.17882/54854). We further examine closure of the sea level budget, comparing the observed global mean sea level with the sum of components. Ocean thermal expansion, glaciers, Greenland and Antarctica contribute by 42 %, 21 %, 15 % and 8 % to the global mean sea level over the 1993–present. We also study the sea level budget over 2005–present, using GRACE-based ocean mass estimates instead of sum of individual mass components. Results show closure of the sea level budget within 0.3 mm/yr. Substantial uncertainty remains for the land water storage component, as shown in examining individual mass contributions to sea level.

Sea level fingerprints due to ongoing land ice melt in altimetry data

2021 ◽  
Author(s):  
Lorena Moreira ◽  
Anny Cazenave
Keyword(s):  
Sea Level ◽  
Regional Scale ◽  
Water Storage ◽  
Altimetry Data ◽  
Ice Melt ◽  
Atmospheric Loading ◽  
Ocean Mass ◽  
Global Mean Sea Level ◽  
Land Water ◽  
Global Mean

<p>The Global Mean Sea Level (GMSL) is rising at a rate of 3.3 mm/year over the altimetry era but at regional scale the behaviour is quite different. In some regions, the sea level rates are up to 2-3 times the global mean rate. The mechanisms behind these discrepancies are explained through the differences in the processes that affect the sea level at different scales. The concept of budget is used to express the superposition of signals that contribute to the change in sea level. At regional scale, apart from the contributions from steric and ocean mass components which are also present in the GMSL budget, the budget is also affected by atmospheric loading component and the static factors component. The static terms (also called fingerprints) include solid Earth’s deformations and gravitational changes in response to mass redistributions caused by land ice melt and land water storage changes. The goal of this study is to detect the fingerprints of the static factors using satellite altimetry-based sea level grids corrected for steric and ocean mass effects. Our preliminary results show a statistically significant correlation between observed and modelled fingerprints in some regions of the oceanic basins.</p>

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